The present invention also relates to the sweep of rotor blade airfoils, more particularly of the first compressor high-pressure stages or of a fan of gas turbines or aircraft gas turbine engines. Owing to the high peripheral speeds of said components, and the practically zero-swirl inlet flow to the blade, supersonic regions occur in the blade tip area with mach numbers in excess of 1.4. These for several reasons negatively affect the performance of this component. Firstly, the efficiency decreases, with increasing blade span, owing to growing shock losses, much more severely than with subsonic rotors. Also, the interaction of duct shock with blade tip swirl negatively affects the stability of the flow, because large blockage regions occur in that area whose nonlinear growth ultimately determines the stability limit of the compressor.
In a broad aspect, the arrangement of the present invention provides means to remedy said problems.
It is a particular object of the present invention to provide a solution to said problems by providing a forward-back-swept blade leading edge. Further objects and advantages of the present invention will become apparent from the subclaims.